Harvey late night: Some final Thursday thoughts

Posted by Eric Berger at 8:25 PM on August 24, 2017

As of 8:00pm CT tonight, a well-organized Hurricane Harvey is moving northwest, toward the Texas coast. It packed 85-mph winds, but forecasters at the National Hurricane Center still expect it to come ashore late Friday night, or Saturday morning as a major hurricane. The most likely landfall location is between Corpus Christi and Port O’Connor. The storm’s strong winds and storm surge, likely at least 10 to 12 feet above normal tide levels, will pack a punch along the central Texas coast. For people in low-lying areas from Corpus to Freeport, these are potentially life-threatening conditions, and I urge you to heed the warnings of the Corpus Christi National Weather Service office and local officials.

For tonight’s post I wanted to discuss the most likely scenario for immediate effects in Houston, and then reconsider the uncertainty about what comes next. The National Hurricane Center anticipates that sustained winds on Friday night and Saturday morning in Houston and Galveston have about an 80 percent chance of reaching 39 mph, or greater. I think that’s possible, and certainly chances are higher southwest of Houston, in places like Sugar Land. However, at this point the available model data indicates that winds will be manageable in the Houston region during Harvey’s landfall. This is important for a number of reasons, not the least of which is that minimal tropical storm force-winds are something the region’s power grid should be able withstand. Mostly.

Harvey’s satellite appearance at 8pm CT Thursday. (NOAA)

In terms of rainfall, the picture is more grim. It still appears as though the Houston region will see manageable rainfall totals through most of Saturday. That is not to say it won’t rain hard at times, and streets may briefly flood. But for the most part I don’t expect mobility to be greatly impaired. If this forecast changes, we will of course be all over it.

Now, looking ahead to the period of Sunday through Wednesday, uncertainty in the track forecast reigns. We’ve hammered this point for a couple of days, but the point remains that we can’t be sure where the storm is going to go after it reaches the coast. It’s like putting a bowling ball down in the middle of an alley—where will it roll? Harvey is going to be something like that. And unfortunately, for us to really get a good, solid handle on rainfall, we ultimately need to know where the center is going to go. Perhaps the best way to handle this is to spitball some probabilities. So let’s discuss three different scenarios.

The Euro special

Odds: 40 percent. Earlier today we discussed the European model solution for Harvey, which brings the storm into the Texas coast, stalls it, then pulls it back over the Gulf of Mexico and eventually into southwestern Louisiana. Under such a scenario, depending upon the track, much of the Houston area would likely get 5 to 25 inches of rainfall, with the greater totals closer to the coast.

The wandering 59 special

Odds: 35 percent. This solution is favored by many members of the GFS model ensemble, in which Harvey comes inland, and wanders around Corpus Christi, and the rest of the Valley until Sunday or Monday. Then it moves up the Highway 59 corridor, into Houston, over Beaumont, and off into Louisiana. Such a scenario would likely bring 10 to 25 inches of rain to much of the Houston metro area, but totals might not necessarily be greatest along the coast.

Dying in the Rio special

Odds: 25 percent. Not all of the GFS ensembles pull Harvey back to the north. Some stay in south Texas and peter out. NOAA’s new hurricane model, the HMON, has depicted such a scenario over the last few runs, too. The HMON forecasts that Harvey’s remnants burn themselves out in northern Mexico and southern Texas. Under this scenario Houston might get 5 to 10 inches of rain from Harvey—a lot of rain, but certainly manageable. If this happens, amore than a few people will be mad at meteorologists for having stood in line at grocery stores today, and now what they heck are they going to do with all these Pop Tarts?

Key takeaways

A major hurricane is coming to the Central Texas coast. It will have bad consequences for that region. However the best available data as of Thursday night suggests the immediate impacts on Houston won’t be extreme.

The unanswered question is what happens to Harvey once it reaches the coast. Where will it go, and will it go fast enough? Houston’s rainfall totals over the next five days depend on this, and we just don’t know.

Big-time floods are coming to Texas. Certainly the Corpus Christi area and points immediately north and west of there will get too much rain. Flooding will spread to other parts of Texas too, quite possibly Houston. But right now we can’t say that for certain. As I’ve said, it’s either going to be pretty bad, or really really bad here.

Eric Berger

G.M.

Thank you for this. I guess essentially what you’re saying is that at this point, there is a great deal of uncertainty about Harvey’s track once it makes landfall, and it would be pointless for you to estimate rainfall totals in specific neighborhoods until the track becomes more clear. So, readers of your blog should check back for updates, listen to their local emergency management officials and prepare for significant rain, wind and storm surge with the hope that nothing unmanageable presents itself?

Armando D.

Thank you Eric for your words today. My dear Fulgencio and I will have our peaceful night tonight and eagerly await seeing what comes next. We are prepared with water and food and other necessities we need and have you to thank. Ciao!

Juan Septien

Thanks again for all the good guidance on this kind of events. My question is relative to the rain totals and how the effects of Harvey could be compared, for instance, to those of the Labor Day 2015 flood?

Lisa Paffel

Eric, the work you’re doing is unbelievable. I can’t tell you how many other news and weather sites I’ve seen today calling this “the most devastating hurricane Houston has seen in a decade” or “more devastating than Allison.”

I like the facts, and the likely scenarios. What you give is truly hype-free. I love that you spend so much time and effort making sure your fellow Houstonians know the truth, and are prepared for what’s going to come.

Lindsey

Could you be more specific of what you expect in the Ft. Bend county area? We are not used to flooding as much, even with a lot of rain, but we are much closer to the action than say downtown Houston. I’m trying to get a better understanding of what we should be prepared for here.

Anne

Jeff

It sounds like we will be okay with the initial landfall, but do you think those in the Clear Lake/Friendswood area (near Ellington Field) should consider evacuating due to what might happen later under the Euro or Wandering 59 scenarios? We’re not too worried about street flooding (we can just stay at home), but would be worried if houses were going to flood.

Cathy

Thank you so much for your frank and clear information, even when things are uncertain. I think we all wish we could have perfect, 100% accurate predictions from meteorologists, and it’s hard to deal with not knowing for sure how much to worry. But I understand that the science is just not at that point yet, and your posts are so helpful and down-to-earth. Please keep doing what you do! Very much appreciated!

Jason

I have a gathering at my house Saturday afternoon near Dacus (northwest of Montgomery). If we wrap up at 4 PM any guesses as to ability to get to homes in northwest Montgomery County and Grimes County? I know it isn’t a realistic question. My dilemma is Saturday afternoon vs evening. Thanks for your posts. Debra

Phil Sudan

There are reports going around Houston that the local news media are hugely underplaying the likely severity of Houston flooding to “curb widespread panic”. According to these reports, there was a meeting today (Thurs) with Army Corp of Engineers and area Flood Control Districts, where it was agreed that flooding in Houston will be “catastrophic” and most of Houston will be without electricity for at least three days. In your view, is the local media coverage reasonably accurate and something I can rely on in making decisions on leaving or staying in Houston? Thanks.

Ayoung

Petey James

Saturday night is fight night. Will the rain/winds be bad enough outside (The Woodlands) to have to watch it at home and not go to the bar? Thinking the fight starts about 9:30, finishes about 9:40, and back home by 10:30.

Amy

Are we going to be able to go to sleep on Friday night without worrying about waking up to water on the floor? I know the answer is no on Saturday and Sunday and maybe Monday….but can we get a good night sleep on Friday?

Jeff

Fiftyohm

Thank you Eric for the update. Actually we go waaay back to the days when people used to ask if a place which shall go unmentioned should evacuate. This came up on a blog I frequent. I hope you, your wife, and daughter are doing well!

Eric Berger

ABC

Love your style. We need more of that in the media (and less all-caps theme graphics). Any way we can get it to come up here to the Hill Country and dump all those 25 inches into our low lakes? Via HAARP or and artificial Low right around Amarillo? Thanks!

Candace

OMG I just moved here from North Texas 5 months ago and was doing the whole shopping thing for prep food and i called my Mom telling her wow there’s no bread, no vienna sausages, then i got to the Pop Tart isle and NOT ONE BOX OF POP TARTS !! Wait why pop tarts lol?? Im so confused lol